Connectionism is the modern form of empiricist philosophy (Berkeley, 1710; Hume, 1748/1952; Locke, 1706/1977), where knowledge is not innate, but is instead provided by sensing the world. “No man’s knowledge here can go beyond his experience” (Locke, 1706/1977, p. 83). If recursion is fundamental to the classical approach’s rationalism, then what notion is fundamental to connectionism’s empiricism? The key idea is association: different ideas can be linked together, so that if one arises, then the association between them causes the other to arise as well.

For centuries philosophers and psychologists have studied associations empirically, through introspection (Warren, 1921). These introspections have revealed the existence of sequences of thought that occur during thinking. Associationism attempted to determine the laws that would account for these sequences of thought. The earliest detailed introspective account of such sequences of thought can be found in the 350 BC writings of Aristotle (Sorabji, 2006): “Acts of recollection happen because one change is of a nature to occur after another” (Sorabji, 2006, p. 54). For Aristotle, ideas were images (Cummins, 1989). He argued that a particular sequence of images occurs because either this sequence is a natural consequence of the images, or because the sequence has been learned by habit. Recall of a particular memory, then, is achieved by cuing that memory with the appropriate prior images, which initiate the desired sequence of images. “Whenever we recollect, then, we undergo one of the earlier changes, until we undergo the one after which the change in question habitually occurs” (Sorabji, 2006, p. 54).

Aristotle’s analysis of sequences of thought is central to modern mnemonic techniques for remembering ordered lists (Lorayne, 2007; Lorayne & Lucas, 1974). Aristotle noted that recollection via initiating a sequence of mental images could be a deliberate and systematic process. This was because the first image in the sequence could be selected so that it would be recollected fairly easily. Recall of the sequence, or of the target image at the end of the sequence, was then dictated by lawful relationships between adjacent ideas. Thus, Aristotle invented laws of association.